CYTOKINES ACTIVE ON GRANULOMONOPOIESIS - RELEASE AND CONSUMPTION BY HUMAN MARROW MYELOID STROMAL CELLS

Haemopoiesis is sustained and preferentially committed to granulomonop oiesis by myeloid stromal cells generated by colony-derived cell lines (CDCL). Using ELISA and RIA, we studied, in the supernatant of cells from CDCL, the time course of interleukins 3 and 6 (IL-3, IL-6), stem cell factor (SCF), granulocyte-macrophage, granulocyte and macrophage colony stimulating factors (GM-CSF, G-CSF and M-CSF), macrophage-infla mmatory protein-1 alpha (MIP-1 alpha) and transforming growth factor b eta 1 (TGF beta 1). IL-6, GM-CSF, M-CSF and MIP-1 alpha were released into the supernatant after medium renewal and, except for M-CSF, addit ion of IL-1 beta. G-CSF was detected only after addition of IL-1 beta. SCE contained in medium, first declined and then increased 24 h after medium renewal. Release of TGF beta 1 started 24 h after medium renew al and lasted until day 7. IL-3, provided by horse serum, declined thr oughout the 7 d of observation. In conclusion, stromal cells from CDCL synthesized and released into the supernatant. IL-6, GM-CSF, G-CSF, M -CSF and MIP-1 alpha after stimulation by seric factor(s) and/or IL-1 beta. TGF beta 1 was synthesized and released without any obvious extr aneous stimuli. There is no definite argument for synthesis of soluble SCF and IL-3. These data support a model where growth factors increas e shortly after medium renewal, and negative regulators take over at a later time.